Disk-loading device

ABSTRACT

A disc loading device that suppresses the occurrence of vibratory oscillation of a tray ( 12 ) immediately after the start of loading or immediately before the end of unloading of the tray ( 12 ), and with which high quality tray loading/unloading can be obtained. A guide groove ( 12   a ) is disposed parallel to a loading/unloading direction in the tray ( 12 ), the groove width dimension of the guide groove ( 12   a ) is reduced only in the vicinity of a tray loading start position or an unloading end position, and a gap between the guide groove ( 12   a ) and guides ( 11   a,    11   b,    11   c ) that engage with the guide groove ( 12   a ) and are disposed at a main chassis ( 11 ) is reduced. Also, lateral pressure is given by an elastic body ( 11   d ) to a side wall of the guide groove ( 12   a ) to thereby press the guide groove ( 12   a ) and the guides ( 11   a,    11   b,    11   c ) into contact during the loading/unloading of the tray, or immediately after the start of loading of the tray, or immediately before the end of unloading of the tray.

TECHNICAL FIELD

The present invention relates to a disc loading device suitably used ina compact disc player.

BACKGROUND ART

Conventional disc loading devices used in, for example, optical discdevices have been configured as shown in FIGS. 7 to 9. FIG. 7 is anexploded view of a disc loading device, FIG. 8 is a perspective viewshowing a tray in an unloaded state, and FIG. 9 is a perspective viewshowing the tray in a loaded state. As shown in FIG. 7, a rotating gear13 is disposed in a main chassis 11, and torque is transmitted to therotating gear 13 from a loading motor (not shown). The rotating gear 13meshes with a rack 12 b disposed at a tray 12, and the rotational motionof the rotating gear 13 is converted to rectilinear motion, whereby thetray is loaded in the main chassis and unloaded from the main chassis.However, because the rack 12 b and the rotating gear 13 are disposed atthe side of the device, the position of the point where the forcepulling the tray 12 into the main chassis 11 acts, which is at theposition where the rack 12 b and the rotating gear 13 mesh, does notcoincide with the center of gravity of the tray 12 at the substantialcenter portion of the disc placement surface. Thus, a moment centeredaround the center of gravity of the tray 12 arises, and the tray 12becomes rotationally displaced. For this reason, immediately after thestart of the loading of the tray from the tray unloaded state of FIG. 8to the tray loaded state of FIG. 9, and immediately before the end ofthe unloading of the tray from the tray loaded state of FIG. 9 to thetray unloaded state of FIG. 8, vibratory oscillation of the tray 12occurs, and an abnormal noise such as rattling occurs.

The displacement amount of the oscillation is a maximum at theunloading-direction distal end portion of the tray 12, and is regulatedby the size of a gap between a guide groove 12 a disposed in both endportions of the tray and guides 11 a, 11 b and 11 c disposed at the mainchassis. This gap is disposed in order to avoid a state where the guidegroove 12 a pressingly fits into and slides in the guides 11 a, 11 b and11 c. The displacement at this distal end portion is dependent on thingsother than the guide groove 12 a and the guides 11 a, 11 b and 11 c;specifically, it is dependent on the distance between the first guide 11a and the second guide 11 b disposed at the main chassis 11, and also onthe depth dimension of the tray 12 or the guide groove 12 a. As forrestrictions on the depth dimension of the device and the unloadingamount of the tray 12, the degree of freedom of the substantial designis extremely small because a stroke equal to or greater than thediameter of the disc is required. Thus, the displacement of theunloading-direction distal end portion of the tray 12 at the time of theoscillation may be said to be controlled by the width of the guidegroove 12 a and the gap with the first guide 11 a and the second guide11 b.

Usually, because the linearity in the loading/unloading direction of theguide groove 12 a is 0.2 mm, it is necessary to make the gap between theguide groove 12 a and each guide 11 a, 11 b and 11 c on the main chassis11 be about 0.25 mm to about 0.35 mm in order to avoid the state wherethe guide groove 12 a and the guides 11 a, 11 b and 11 c pressingly fittogether and slide at the time of loading/unloading.

As usual design values, in a case where, for example, the distancebetween the first guide groove 11 a and the second guide groove 11 b is35 mm, and where the distance from the position where the rotating gear13 in the tray unloaded state drives the rack 12 b to theunloading-direction distal end portion of the tray 12 is 175 mm, thedisplacement amount at the unloading-direction distal end portion of thetray 12 at the time of the oscillation becomes about five times the gapbetween the guide groove 12 a and each guide 11 a, 11 b and 11 c. Whenthe gap is 0.25 mm, the displacement amount becomes about 1.25 mm, andwhen the gap is 0.4 mm, the displacement amount becomes about 2.00 mm.

In this manner, the vibratory oscillation immediately after the start ofthe unloading of the tray and immediately before the end of theunloading of the tray causes the operating quality to significantlydrop, but this does not become a problem in terms of operating qualityas long as the displacement of the tray unloading-direction distal endportion can be held to about 1 mm or less. Thus, even if oscillationarises, this does not become much of a problem in terms of operatingquality as long as the gap between the guide groove 12 a and the guides11 a, 11 b and 11 c on the main chassis 11 can be managed to 0.2 mm orless. However, in the conventional disc loading device, the gap betweenthe guide groove 12 a and the guides 11 a, 11 b and 11 c on the mainchassis 11 has not been able to be set to 0.2 mm or less because, asmentioned above, the precision of the linearity of the guide groove 12 adisposed in the tray 12 has been about 0.2 mm.

The reason for this is because when the gap is lower than 0.2 mm, theproblem arises that when the guide groove 12 a is guided by the guides11 a, 11 b and 11 c on the main chassis, it pressingly fits into andslides, leading to a remarkable drop in the operating speed in the tray12 due to an increase in the operating load, and the motor (not shown)cannot drive the tray 12.

DISCLOSURE OF THE INVENTION

The present invention has been made in order to solve theabove-described problem, and it is an object thereof to obtain a discloading device where, because vibratory oscillation of the tray 12 issuppressed to an extent that it does not become a problem in terms ofoperating quality, the problems of an extreme drop in speed andinoperability do not occur even if the gap between the guide groove 12 aand the guides 11 a, 11 b and 11 c on the main chassis 11 is configuredto be 0.2 mm or less, and to obtain a disc loading device that cansuppress vibratory oscillation of the tray 12 without dependency on thegap between the guide groove 12 a and the guides 11 a, 11 b and 11 c onthe main chassis 11.

The disc loading device pertaining to this invention comprises: a trayin which a disc is placed; a main chassis into which the tray is loadedand from which the tray is unloaded; a guide groove disposed parallel toa loading/unloading direction in the tray or the main chassis; andguides that are disposed at the main chassis or the tray and engage withthe guide groove, wherein the width of the guide groove in the vicinityof a loading start position or an unloading end position of the tray isformed narrower than the width at another portion.

Also, the disc loading device pertaining to this invention comprises: aguide groove disposed parallel to a loading/unloading direction in thetray or the main chassis; guides that are disposed at the main chassisor the tray and engage with the guide groove; and an elastic body thatpresses a side wall of the guide groove and the guides into contact atthe time of loading/unloading of the tray.

Moreover, the disc loading device pertaining to this inventioncomprises: a guide wall disposed in the main chassis or the tray; alateral pressure wall disposed parallel to a loading/unloading directionin the tray or the main chassis; and an elastic body that presses theguide wall and the lateral pressure wall into contact at the time ofloading/unloading of the tray.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view in an instance where a guide groove ina tray unloaded state of a disc loading device pertaining to a firstembodiment of the invention is seen from below a main chassis.

FIG. 2 is an exploded view of a disc loading device of a secondembodiment of the invention.

FIG. 3 is a perspective view of relevant portions of the disc loadingdevice of the second embodiment of the invention.

FIG. 4 is a cross-sectional view in an instance where a guide groove ina tray unloaded state of the disc loading device of the secondembodiment of the invention is seen from below the main chassis.

FIG. 5 is a cross-sectional view in an instance where a guide groove ina tray unloaded state of a disc loading device of a third embodiment ofthe invention is seen from below the main chassis.

FIG. 6 is a cross-sectional view in an instance where a guide groove ina tray unloaded state of a disc loading device of a fourth embodiment ofthe invention is seen from below the main chassis.

FIG. 7 is an exploded view showing a conventional disc loading device.

FIG. 8 is a perspective view of the conventional optical disc deviceshowing a tray in an unloaded state.

FIG. 9 is a perspective view of the conventional optical disc deviceshowing the tray in a loaded state.

BEST MODE FOR IMPLEMENTING THE INVENTION Embodiment 1

FIG. 1 shows a disc loading device of a first embodiment of theinvention, and is a cross-sectional view in an instance where a guidegroove 12 a in the vicinity of a loading start position of a tray 12 isseen from below a main chassis 11. The tray 12, in which a disc isplaced and in which the guide groove 12 a parallel to aloading/unloading direction is disposed, is loaded in and unloaded fromthe main chassis 11, in which guides 11 a and 11 b that engage with theguide groove are disposed.

The guide groove 12 a includes a section A where the width in thevicinity of the loading start position of the tray 12 is narrowlyformed. The section A is configured so that a gap between the guidegroove 12 a and the guides 11 a, 11 b and 11 c is 0.1 mm to 0.2 mm. Thegap between the guide groove 12 a and the guides 11 a, 11 b and 11 c inthe section A is determined by the linearity of the guide groove 12 a,and the linearity is proportion to the length of the guide groove. Inthe instance of the first embodiment, the total length of the guidegroove is 200 mm, whereby precision of about 0.05 mm can be easilyobtained by making the length of the section A about 45 mm, and theconfiguration at the gap becomes possible. Because the width of theguide groove 12 a at the portion other than the section A is formed sothat the gap with the guides 11 a, 11 b and 11 c becomes 0.25 mm to 0.35mm, loading/unloading at a light load is conducted without there arisinga reduction in the gap with the guides 11 a, 11 b and 11 c after theguides 11 a, 11 b and 11 c pass through the section A and an increase inload resulting from constriction.

In the disc loading device configured in this manner, the loading of thetray 12 starts as a result of a rotating gear 13 being rotationallydriven by a loading motor (not shown) from the state of FIG. 8, which isa tray unloaded state. When the loading starts, the torque of the motoris transmitted to a rack 12 b from the rotationally driven rotating gear13, and the rotational motion of the rotating gear 13 is converted bythe rack 12 b to rectilinear motion. As a result, the guide groove 12 ais guided by the guides 11 a, 11 b and 11 c, whereby the tray 12 isloaded in the main chassis 11 and finally reaches the loaded state shownin FIG. 9.

When the tray 12 is loaded in the main chassis 11, the disc is retainedby a damper 18 shown in FIG. 9 and a turntable (not shown), and trayloading ends.

The loading of the tray 12 is conducted as described above, butimmediately after the start thereof, similar to the conventional discloading device, vibratory oscillation temporarily arises due to themoment around the center of gravity of the tray resulting from a shiftbetween the position of the center of gravity of the tray and the pointwhere the force with which the rotating gear 13 drives the rack 12 bacts. However, the displacement of this oscillation becomes a maximum of1 mm at the unloading-direction distal end position of the tray 12because the gap between the guide groove 12 a and the guides 11 a, 11 band 11 c is a maximum of 0.2 mm, so that high quality tray loading isconducted, and the occurrence of abnormal noises can be suppressed.

Because the oscillation is suppressed, relative motion between the tray12 and the disc placed in the tray 12 is also suppressed. For thisreason, damage to the disc recording surface resulting from accompanyingrelative motion between the disc recording surface and the trayplacement surface can be prevented. Also, at the time the disc is to beretained, there is little shift between the center of the disc and thecenter of the disc retention unit comprising the turntable (not shown)and the damper 18, and retention of the disc can be smoothly conducted.

The unloading of the tray 12 also starts as a result of the rotatinggear 13 being rotationally driven by the motor (not shown), and the sameoscillation seen immediately after loading of the tray 12 also occursimmediately before the end of the unloading of the tray 12. However, inthis instance also, similar to the loading of the tray 12, thedisplacement at the unloading-direction distal end position of the tray.12 is a maximum of 1 mm, and high quality unloading of the tray 12 isconducted.

By disposing at least two guides that engage with the portion of theguide groove where the width is narrowly formed, the parallel statebetween the loading/unloading direction and the guide groove is morereliably maintained at the time loading starts and at the time unloadingends, and the higher quality tray unloading can be obtained.

Embodiment 2

FIGS. 2 to 4 are diagrams showing a second embodiment of the invention.FIG. 2 is an exploded view of the disc loading device of the secondembodiment of the invention, FIG. 3 is a perspective view of relevantportions of the disc loading device of the second embodiment of theinvention, and FIG. 4 is a cross-sectional view in an instance where theguide groove 12 a in the tray unloaded state of the disc loading deviceof the second embodiment of the invention is seen from below the mainchassis 11.

The configuration of the second embodiment is substantially the same asthat of the first embodiment, except that in the second embodiment, thegap between the guide groove 12 a and the guides 11 a, 11 b and 11 c isconstant (e.g., 0.25 mm to 0.35 mm) across the total length of the guidegroove 12 a to the extent that fitting together and sliding can beprevented, and an elastic body 11 d (e.g., a plate spring), whichpresses at least one side wall of the guide groove 12 a and the guides11 a, 11 b and 11 c into contact in the X direction shown in thedrawings or the direction opposite to this at the time ofloading/unloading of the tray 12, is integrally disposed at the mainchassis 11.

In the present embodiment also, the loading/unloading of the tray 12 isconducted in the same manner as in the first embodiment, and the gapbetween the guide groove 12 a and the guides 11 a, 11 b and 11 c ispresent (0.25 mm to 0.35 mm) similar to the conventional device, wherebythe vibratory oscillation. immediately after the start of the loadingand immediately before the end of the unloading of the tray 712similarly arises. However, because the side wall of the guide groove 12a is pressed by the elastic body 11 d into contact with the guides 11 a,11 b and 11 c, the oscillation is suppressed, and similar to the firstembodiment, high quality loading/unloading of the tray 12 is conducted.

Embodiment 3

FIG. 5 shows the disc loading device of a third embodiment of theinvention, and is a cross-sectional view in an instance where the guidegroove 12 a in the tray unloaded state of the disc loaded device is seenfrom below the main chassis 11.

The third embodiment is one where the second embodiment is developed,and the configuration is substantially the same as that of the secondembodiment, except that in the third embodiment, a step 13 is disposed,in the vicinity of the loading start position of the tray 12, in theside wall of the guide groove 12 a that is acted upon by lateralpressure due to the elastic body 11 d.

The loading/unloading of the tray 12 is conducted in the same manner asin the second embodiment, and the vibratory oscillation immediatelyafter the start of loading and immediately before the end of unloadingof the tray 12 is similarly generated. However, because the side wall ofthe guide groove 12 a is pressed into contact with the guides 11 a, 11 band 11 c by the elastic body 11 d, the oscillation is suppressed, andhigh quality loading/unloading of the tray 12 is conducted similar tothe first embodiment.

Also, in the vicinity of the loading start position of the tray 12, thestep 13 is disposed in the side wall of the guide groove 12 a that isacted upon by lateral pressure due to the elastic body 11 d. Thus, thedisplacement of the elastic body 11 d in the vicinity of the loadingstart position becomes larger than the displacement at another portion.As a result, lateral pressure can effectively act on the side wall ofthe guide groove 12 a only in the vicinity of the loading start positionof the tray 12. Thus, the driving force necessary to load/unload thetray 12 can be reduced in comparison to the second embodiment in termsof the overall operation. Namely, when the motor is driven at a constantvoltage, the loading/unloading of the tray 12 can be conducted with alight load, and the operating speed of the tray 12 can be loweredenormously. Also, because the friction between the side wall of theguide groove 12 a and the press-contact portion of the elastic body 11 daccompanying repeated loading/unloading of the tray 12 can be reduced,the change in the lateral pressure acting on the tray 12 is slight evenafter loading/unloading of the tray 12 has been repeated numerous times,and high quality loading/unloading of the tray 12 can be conducted overa long period of time. This effect becomes larger as the displacement ofthe elastic body 11 d other than in the vicinity of the loading startposition of the tray 12 approaches zero.

In an instance where the guides 11 a, 11 b and 11 c are plurallydisposed in the vicinity of the loading start position of the tray 12,as in the second and third embodiments, elastic bodies 11 d are disposedbetween adjacent guides 11 a, 11 b and 11 c, whereby the side wall ofthe guide groove 12 a pressingly contacts the same-direction sidesurfaces of adjacent guides 11 a, 11 b and 11 c. Thus, theloading/unloading of the tray 12 is conducted in a state where theparallelism between the main chassis 11 and the tray 12 is maintained,so that higher quality loading/unloading is obtained. Also, in aninstance where the elastic body is plurally disposed in the vicinity ofthe loading start position of the tray 12, the same effect is obtainedeven if the guides 11 a, 11 b and 11 c are disposed between adjacentelastic bodies.

Embodiment 4

FIG. 6 is a diagram showing a fourth embodiment of this invention, andis a cross-sectional view in an instance where the guide groove 12 a inthe tray unloaded state of the disc loading device is seen from belowthe main chassis 11.

A lateral pressure wall 12 c is disposed in the tray 12 parallel to theloading/unloading direction, and a guide wall lie is disposed in themain chassis 11 parallel to the lateral pressure wall 12 c. The tray 12,in which a disc is disposed, is loaded in and unloaded from the mainchassis 11 by the lateral pressure wall 12 c and the guide wall lie.Additionally, the lateral pressure wall 12 c and the guide wall lie arepressed into contact, at the time of the loading/unloading of the tray12, by elastic bodies 11 d disposed in the main chassis 11.

The guide wall 11 e does not have to be continuously disposed parallelto the lateral pressure wall 12 c as shown in FIG. 6, but may bedisposed intermittently in pairs with the elastic bodies 11 d, forexample.

The loading/unloading of the tray 12 is conducted in the same manner asin the first embodiment. The lateral pressure wall 12 c disposed in thetray 12 is guided by the guide wall lie disposed parallel to the lateralpressure wall 12 c, whereby the tray 12 is loaded in the main chassis 11and finally reaches the loaded state shown in FIG. 9. In the fourthembodiment also, vibratory oscillation immediately after the start ofloading or immediately before the end of unloading of the tray 12 occursin the same manner as the in the first embodiment. However, because thelateral pressure wall 12 c is pressed into contact with the guide walllie by the elastic bodies 11 d, the oscillation is suppressed, and highquality loading/unloading of the tray 12 is conducted.

By disposing at least two elastic bodies 11 d in the vicinity of theloading start position, the parallel state between the guide wall lieand the lateral pressure wall 12 c is maintained during theloading/unloading of the tray 12, whereby higher quality trayloading/unloading can be obtained.

Also, by disposing a step in the guide wall 11 e and reducing thelateral pressure given to the other portion to be lower, to an extentthat does not affect the loading/unloading operation of the tray 12,than the lateral pressure given to the guide wall 11 e in the vicinityof the loading start position, high quality loading/unloading of thetray 12 over a long period of time can be obtained in the same manner asin the third embodiment.

The guide groove 12 a and the guides 11 a, 11 b and 11 c of the first,second and third embodiments, and the guide wall 11 e and the lateralpressure wall 12 c of the fourth embodiment, may be disposed in eitherthe tray 12 or the main chassis 11. The same is true of the elastic body11 d of the second, third and fourth embodiments.

Also, the elastic body 11 d does not have to be a plate spring; itsuffices as long as the elastic body 11 d can give appropriate lateralpressure to the side wall of the guide groove 12 a or the lateralpressure wall 12 c, such as rubber or a coil spring.

Also, the elastic body 11 d may be configured separately from the mainchassis 11 or the tray 12 as needed, but by forming the elastic body 11d integrally with the main chassis 11 or the tray 12 as in the second tofourth embodiments, a disc loading device whose operating quality ishigh can be obtained without adding new parts to a conventional discloading device.

INDUSTRIAL APPLICABILITY

As described above, the disc loading device pertaining to this inventioncan be used not only in compact disc players but in various types ofdisc loading devices like DVD players.

1. A disc loading device comprising: a tray in which a disc is placed; amain chassis into which the tray is loaded and from which the tray isunloaded; a guide groove disposed parallel to a loading/unloadingdirection in the tray or the main chassis; and guides that are disposedat the main chassis or the tray and engage with the guide groove,wherein the width of the guide groove in the vicinity of a loading startposition or an unloading end position of the tray is formed narrowerthan the width at another portion.
 2. The disc loading device of claim1, wherein a gap between a side wall of the guide groove, at the portionwhere the width of the guide groove is narrowly formed, and the guidesthat engage with the side wall is 0.1 mm to 0.2 mm.
 3. The disc loadingdevice of claim 1 or 2, wherein at the time of the start of loading orat the time of the end of unloading of the tray, there are at least twoguides that engage with the side wall of the portion where the width ofthe guide groove is narrowly formed.
 4. A disc loading devicecomprising: a tray in which a disc is placed; a main chassis into whichthe tray is loaded and from which the tray is unloaded; a guide groovedisposed parallel to a loading/unloading direction in the tray or themain chassis; guides that are disposed at the main chassis or the trayand engage with the guide groove; and an elastic body that presses aside wall of the guide groove and the guides into contact at the time ofloading/unloading of the tray.
 5. The disc loading device of claim 4,wherein at the time of loading/unloading of the tray, a displacementamount of the elastic body in the vicinity of a loading start positionor an unloading end position of the tray is larger than a displacementamount at another portion.
 6. The disc loading device of claim 4 or 5,wherein the guides are plurally disposed in the vicinity of the loadingstart position or the unloading end position of the tray, and theelastic body is disposed between adjacent guides.
 7. The disc loadingdevice of claim 4 or 5, wherein the elastic body is plurally disposed inthe vicinity of the loading start position or the unloading end positionof the tray, and the guides are disposed between adjacent elasticbodies.
 8. A disc loading device comprising: a tray in which a disc isplaced; a main chassis into which the tray is loaded and from which thetray is unloaded; a guide wall disposed parallel to a loading/unloadingdirection in the main chassis or the tray; a lateral pressure walldisposed parallel to the guide wall in the tray or the main chassis; andan elastic body that presses the guide wall and the lateral pressurewall into contact at the time of loading/unloading of the tray.
 9. Thedisc loading device of claim 8, wherein at least two elastic bodies aredisposed in the vicinity of a loading start position or an unloading endposition of the tray.
 10. The disc loading device of claim 4, whereinthe elastic body is disposed integrally with the main chassis or thetray.